Methods of refining petroleum products



2,823,17 3 METHODS OF REFINING PETROLEUM PRODUCTS Andre Gislon, Paris,and Joseph Marie Quiquerez, Gonfreville IOrcher, France, assignors toSociet Anonyme dite: Compagnie Francaise de Rafiinage, Paris, France, acorporation of the French Republic No Drawing. Application March 6, 19531 Serial N0. 340,918

15 Claims. (Gl'. 196-29) This invention relates to improved methods ofrefining petroleum products and is particularly suited for thesweetening of gasoline, kerosene, solvents and other cracked ordistilled petroleum products.

As we have disclosed inour co-pending application, Serial No. 133,058,filed December 15, 1949, now Uni-ted States Patent 2,659,691, of whichthis application is a continuation-in-part, we discoveied that certainchelate compounds, when added to petroleumproducts containingappreciable quantities of sulfur in the mercapta n form, catalyze theoxidation of the mercaptans and yield sweet product s.

Without guessing at the mechanism of the action of said chelatecompounds, We have now discovered that the sweetening ofmercaptan-bea-ring petroleum products may be efiectively andeconomically achieved by forming chelate compounds in theproductundergoing treatment by brin in together certain S'c'hifi? basesand cdntpeunds of group VIII metals of the periodic table. ('jt'he'rwisestated, we found that it is 'adt anfageeus to fonn such chelatecompounds in situ in the product being refined. In practicing ourinvention, we presently prefer chelate compounds containing cobalt-,such as are made by introducing certain iminophenols into the petroleumproduct to be treated and then adding a solution of a cobalt compound.Thereafter,.the sweetening operation is carried out in the presence ofoxygen or an oxygen-containing gas, although in certain instances theoxygen-dissolved in the petroleum product Willbe' sufficient. v

The features of the invention can perhaps best be, appreciated byreference to specific examples as follows:

EXAMPLEI To one liter of a petroleum spirit which had an end boilingpoint of 200 6., obtained from an Iraq crude oil and containing 0.033%by weight or sulfur as mercaptans, we added 33 mg. of the Schiff baseresulting from the action of salicyl aldehyde on ethylene diamine. Tothis oil' was added 100cm. of a 10% solution of cobalt acetate inmethanol; the mixture was agitated with air for one hour and then leftto stand. The analytic results of this treatment are set? forth below inTable 1 in terms ofthe diminishing m'er'eaptan content as a function oftime.

Tabl 1 Weight percent Time mercaptans 3 minutes... 0.028 0.015

EXAMPLE 2 One liter of a straight run Iraq petroleum spirit having; anend boiling point of 200 C. and containing 0.033% by weight of sulfur asmercaptan was treated with 40 mg. of disalicylal diimine propylene and10.2 mg.- of cobalt in theform of cobalt oleate;

The Schiff base is introduced into the petroleum spirit either dissolvedin toluene or in an alcohol, though the latter is preferable as is shownin the accompanying Table 2 which illustrates the disappearance of themercaptans After 1 hour in the oil with time as the treated oil isallowed to stand.

Table 2 Charge of Petroleum Spirit Initial percent of sulfur as nerca'ptttns'tby vol)... Grams of disalicylal propylene dilmine added.Solvent for thedisalicylal. 1 Grams cobalt added (in form of oleatWeight percent sulfur (as mercaptaus After 6 hours, After 24 holirs Wealso found that the sweetening; treatment is greatly accelerated by thepresence of alkali as is brought out in the following example. v

EXAMPLE 3 As will be seen in the Table 3a, the use of alkali makes oneliter batches of the Iraq petroleum spirit of Example 2, equalquantities of cobalt oleate and disalicylal propylene diimine butvarying the solvent for the Schiff base and in some instances, addingalkali. The test batches were agitated with air, allowed to rest, andthe meroaptan content measured; The results of these tests are set forthin Table 3.

Table 3 Number of test 1 2 3 4 5 Oharge'of Petroleum Spirits. 1,0000111.... 1,000.ein. 1,000 cm)- 1,0001'2m. 1,000 cm. Percent S asmercaptans (by vol.) 0.0237 0.0 0.0237 0.0237. Gramsdisallcylalvpropylene dllmine added. .0 0.040. Solvent forthe semi? baseToluene Grams cobalt added (asoleate) 2.; 0.0102. Other reagents; 20 em,of 10% NaOH Metli.

soln.

harm BY waten r or s is MeaexeTAN 3 As will be seen in the-Table 3a, theuse of alkali makes it possible to very appreciably reduce the amountsof reagents used to obtain the desired sweetening in a given time.

We have also found that the condensation products of aromatic compoundshaving an orthohydroxyaldehyde structure-the prototype of which isorthohydroxybenzaldehyde-on aromatics or hydroaromatics cyclic diaminesNumber of test 1 Y 2 g a 4 a 6 Charge of Petroleum spirits 1,000 cm}..-1 ,000 0111. 1,000'cmfi.-. 1,000 emfl--. 1,000 0111. 1,000 cm 3 Gram Sin charge as mercaptans.- 0.252 0.252 0.252.. 0.252 .1 0.252..-. 0.252.Grams disalicylal propylene (11- 0.032 0.024 0.016 0.008 .016 0.008.

lmine added (in solution in 1% methanol). Milllgms. added (as oleate)8.16 6.12 4.08 2.04 Otherreagents None None None None 50 cm. of% emfiof10% As pointed out above, the present invention is not limited to theuse of fatty acid salts of the Group VIII metals. For instance, one mayuse other compounds of cobalt such as naphthenates, alkylphtalates,.alcoholates', enolates, phenolates, alkylphenolates, aminophenolates,and so on, and more, generally any cobalt compound which is soluble inthe hydrocarbons. Moreover, the cobalt compound (or other groupVIHmetal) may be added to the oil being treated in an excess of alcohol,phenol or of an alkyl phenol. Particular instances of the applicationsof these discoveries are hereinafter pointed out.

EXAMPLE 4 We took one liter of a straight-run gasoline derived from aMiddle East crude oil. This gasoline had a final boiling point of 205 C.and contained 0.029% by Weight of sulfur as mercaptans; to this samplewe added 0.040

gram of disalicylal propylene diimine and then we added 0.15 gram of amixture of cresol and cobalt cresolate, the total cobalt being addedthus amounting to 0.0102 gram. We agitated the resulting solutioninthepresence of air and allowed it to stand. After some three hours,the gasoline sample contained no more than 0.006% sulfur in the form ofmercaptans.

EXAMPLE 5 To one liter of gasoline containing 0.035% by weight of sulfuras mercaptans We added 1.6 cm. of a solution of 1% of disalicylalethylene diimine in methanol. We next added 0.0177 gram of acetylacetonate of cobalt, this being equivalent to, or corresponding to0.0021 gram of cobalt. Six hours after the addition of these reagentsthe mercaptan content of the gasoline had dropped to 0.004% as sulfur.

While we presently prefer to use Schiff bases resulting from thecondensation of orthohydroxybenzaldehyde with an aliphatic diamine, itis within the scope of this invention to use Schiif bases resulting frommore or less complex diamines reacted with orthohydroxybenzaldehydeshaving other substituents on the aromatic ring. Suitable amines includeethylene or propylene diamine, diaminodimethylamine,diaminodipropylamine, andso on.

specific example is the use of diaminodipropylamine,

We added to 1 liter of gasoline, initially. containing 0.033% sulfur inthe form of mercaptans, 0.020 gram of disalicylal dipropylaminodiimineand 0.00485 gram of also produces in conjunction with cobalt salts,chelate compounds which are likewise capable of being formed in situ inthe petroleum products, and thus make possible the sweetening of theseproducts by oxidation of the mercaptans, in accordance with thecharacteristics as above defined.

The compounds have the general formula:

/OH HO Ar Ar CH=NAr-N=CH in which: Ar represents aromatic, benzenic,naphtenic or similar radicals, simple or substituted, and Ar representsa cyclic, aromatic or hydroaromatic radical, simple or substituted. Thefollowing examples illustrate these specific embodiments of the refiningprocess according to our invention.

EXAMPLE 7 EXAMPLE 8 As in the preceding example, 10 liters of MiddleEast gasoline having an end point of 200 C.containing 0.030% sulfur inthe form of mercaptansis treated with cobalt oleate and 0.22 g. ofdisalicylal-naphtylenediimine, obtained by condensation of thesalicylaldehyde on the 1-8-diamino-naphtalene: After five hours thepetrol contains 0.003% sulfur in the form of mercaptans.

EXAMPLE 9 1,000 cm. of Middle East gasoline having an end 7 point of 200C., containing 0.033% sulfur in the form of on the l-2 diaminocyclohexane.

After three hours itwill be found that the petrol concobalt as theoleate thereof. To these we added 50 cm. --tains less than 0.002%sulfurin the form of mercaptans. of a 10% aqueous solution of NaOH; afterthreeflhours fallen to 0.004%, as sulfur.

While the foregoing specific examples are concerned the concentration ofthe mercaptans in the gasoline had with the treatment of gasoline, theinvention also encomleum products such as heavy gasolines, whitespirits, kerosenes and so forth, as is described in the followingillustrative examples.

EXAMPLE EXAMPLE 1 1 Similarly, we added 0.010 gram of cobalt stearateand 0.040 gram of disalicylal propylene diimine to one cubic meter of akerosene having a boiling range of 200250 C. and containing 0.031%sulfur in the form of mercaptans. This was then air agitated with a 10%aqueous solution of caustic soda and allowed to rest. After 20 hours themercaptan sulfur content had dropped to It is also within the scope ofour invention to practice the process in a continuous manner. Forexample, one may continuously introduce into a mechanical or bafflemixer the petroleum product to be sweetened, the charge productcontaining therein a small quantity of an appropriate Schiff base, adilute water or alcohol-water solution of alkali, and a small stream ofcharge which contains a small percentage of a group VIII metal compound.Air may also be supplied if the charge of oil is deficient in dissolvedoxygen. The emulsion formed in the mixer is then conducted to a decanterwherein it separates to an alkali-alcohol-water or alkali dilute waterphase which is recycled to the mixer and the sweetened product which iscontinuously withdrawn from the decanter.

EXAMPLE 12 but containing 0.2 gram per liter of cobalt in the form ofcobalt oleate or cobalt ricinoleate. The emulsion formed in the presenceof oxygen was continuously decanted, the sweetened gasoline separatedand the recovered alkali-alcohol-water phase recycled in at theindicated rate.

EXAMPLE 13 A static or mechanical mixer is continuously fed by 100 l./h.with a 10% solution of caustic soda in a mixture of equal volumes ofwater and methanol. This mixture received on the one hand, 1000 litresper hour of Iraq petrol-containing 0.030% sulfur in the form ofmercaptans, to which has been added 0.010 g./l. of the Schifi baseresulting from the condensation of the salicylaldehyde onorthophenylenediamine-and on the other hand, 10 litres per hour of thesame petrol containing 0.2 g./l. of cobalt in the form of an oleate. Theemulsion formed in the mixer is poured off, givinga hydroalcoholicalkaline phase which is re-cycled to the mixer, and a petrol containingless than 0.001% sulfur in the form of mercaptans.

EXAMPLE 14 In still another embodiment of this aspect of our invention,we sweetened a straight run petroleum spirit which had an end point of200 C. and contained 0.033% sulfur as mercaptans to a final sulfurcontent of 0.003%. We added 0.040 gram per liter of disalicylal ethylenediimine and 1% of methanol to the unsweetenedspirit and then circulatedit through a bed composed of an acti vated carbon charged with cobaltnitrate. The effluent, treated gasoline was then either washed withwater or with a dilute soda solution and the methanol thus removed fromthe spirit was recovered by known means.

While in certain instances, the sweetening treatments described leavethe sweetened product somewhat colored, such color may advantageously beeliminated by decanting, water washing, dilute alkali washing, orfiltration through decolorizing clay, depending upon the particularconditions of a given use.

While in the foregoing specification we have particularly pointed outand described specific examples of our invention, and certainmodifications and alternatives, it is to be noted that these are notintended to be exhaustive of the invention but on the contrary arepresented with a view to illustrating and explaining the invention, theprinciples thereof and the best manners of applying it in practical usein order that others skilled in the art may be enabled to practice theinvention and apply it under various circumstances and in various wayseach as may be best suited to the conditions of a particular use.

We claim:

1. The process of sweetening a liquid petroleum product which comprisesadding to said product in the presence of oxygen a minor quantity of animinophenol and a minor quantity of a group VIII metal compound in aform miscible with said petroleum product to thereby form in situ insaid product an organic compound of said group VIII metal having atleast one chelate bond.

2. The process of sweetening a liquid petroleum product which comprisesoxidizing mercaptans therein in the presence of oxygen while there ispresent in the petroleum product itself a small quantity of animinophenol and a minor quantity of a group VIII metal compound in aform miscible with said petroleum product.

3. The process of sweetening a liquid petroleum product which comprisesoxidizing mercaptans therein in the presence of oxygen while there ispresent in the petroleum product itself small quantities of animinophenol and a cobalt compound in a form miscible with said petroleumproduct.

4. The process of sweetening a liquid petroleum product which comprisesoxidizing mercaptans therein in the presence of oxygen while there ispresent in the petroleum product itself a small quantity of a cobaltcompound in a form miscible with said petroleum product and a smallquantity of a Schiif base.

5. The process according to claim 4 wherein said Schiif base is formedby the condensation of an aliphatic diamine with an aromaticorthohydroxyaldehyde.

6. The process according to claim 4 wherein said Schifi base is formedby the condensation of an aromatic orthohydroxyaldehyde on an aromaticcyclic diamine.

7. The process according to claim 4 wherein said Schiff base is formedby'the condensation of an aromatic orthohydroxyaldehyde on anhydroaromatic cyclic diamine.

8. The process according to claim 4 wherein said Schifi base is formedby the condensation of an aromatic orthohydroxyaldehyde on an aromaticcyclic diamine with simple rings.

9. The process according to claim 4 wherein said Schiff base is formedby the condensation of an aromatic ortho hydroxyaldehyde on an aromaticcyclic diamine with condensed rings.

10. The process according to claim 4 wherein said Schifi base is formedby the condensation of an aromatic orthohydroxyaldehyde on an aromaticcyclic diamine with branched rings.

11. The process according to claim 4 wherein said Schiif base is formedby the condensation of an aromatic orthohydroxyaldehyde on anhydroaromatic cyclic diamine with simple rings.

12. The process according to claim 4 wherein said Schiff base is formedby the condensation of an aromatic orthohydroxyaldehyde on anhydroaromatic cyclic diamine with condensed rings.

13. The process according to claim 4 wherein said Schitf base is formedby the condensation of an aromatic orthohydroxyaldehyde on anhydroaromatic cyclic diamine with branched rings.

14. The continuous process of sweetening a liquid petroleum productwhich comprises supplying said petroleum product to a mixing zone,maintaining a concentration of free oxygen in said reaction zonesufficient to oxidize mercaptans therein, supplying a dilute causticwater-alcohol solution to said zone, supplying an iminophenol to thezone while also introducing to said zone a small stream of saidpetroleum product containing a minor quantity of a group VIII metalorganic compound in a form miscible with said petroleum product,conducting the efiluent stream from the mixing zone to a separationzone, removing the aqueous phase from the separation zone and recyclingit to the mixing zone.

15. The continuous process of sweetening a liquid petroleum productwhich comprises supplying said petroleum product to a mixing zone,maintaining a concentration of free oxygen in said reaction zonesufficient to oxidize mercaptans therein, supplying a dilute causticaqueous solution to said zone, supplying an iminophenol to the zonewhile also introducing to said zone a small stream of said petroleumproduct containing a minor quantity of a group VIII metal organiccompound in a form miscible with said petroleum product, conducting theeflluent stream from the mixing zone to a separation zone, removing theaqueous phase from the separation zone and recycling it to the mixingzone.

References Cited in the file of this patent UNITED STATES PATENTS2,523,549 Axe Sept. 26, 1950 2,608,521 Hoog Aug. 26, 1951 2,651,595Moulthrop Sept. 8, 1953 2,659,691 Gislon Nov. 17, 1953 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,823,173 February11, 1958 Andre Gislon et a1,

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 2, line 33, Table 2, second column thereof, opposite "Weightpercent sulfur (as mercaptans) for "0008" read 0,033 same column 2, line34, Table 2, second column thereof, opposite "After 1 hour", for "0.033"read 0,008

Signed and sealed this 10th day of February 1959,

(SEAL) Attest:

KARL AXLINE ROBERT c. WATSON Attesting Oflicer Commissioner of Patents

1. THE PROCESS OF SWEETENING A LIQUID PETROLEUM PROD-UCT WHICH COMPRISESADDING TO SAID PRODUCT IN THE PRESENCE OF OXYGEN A MINOR QUANITY OF ANIMINOPHENOL AND A MINOR QUANTITY OF A GROUP VIII METAL COMPOUND IN AFORM MISCIBLE WITH SAID PETROLEUM PRODUCT TO THEREBY FORM IN SITU INSAID PRODUCT AN ORGANIC COMPOUND OF SAID GROUP VIII METAL HAVING ATLEAST ONE CHELATE BOND.
 4. THE PROCESS OF SWEETENING A LIQUID PETROLEUMPRODUCT WHICH COMPRISES OXIDIZING MERCAPTANS THEREIN IN THE PRESENCE OFOXYGEN WHILE THERE IN PRESENT IN THE PETROLEUM PRODUCT ITSELF A SMALLQUANTITY OF A COBALT COMPOUND IN A FORM MISCIBLE WITH SAID PETROLEUMPRODUCT AND A SMALL QUANTITY OF A SCHIFF BASE.